The present disclosure describes systems and techniques relating to processing information received from a spatially diverse transmission.
Mobile phones, laptops, personal digital assistants (PDAs), base stations and other systems and devices can wireless transmit and receive data. Such systems and devices have used orthogonal frequency division multiplexing (OFDM) transmission schemes, such as those defined in the Institute of Electrical and Electronics Engineers (IEEE) 802 wireless communications standards. The IEEE 802 standards include IEEE 802.11a, 802.11g, 802.11n, and 802.16. In an OFDM system, in particular, a data stream is split into multiple substreams, each of which is sent over a different subcarrier frequency (also referred to as a tone or frequency tone).
Some wireless communication systems use a single-in-single-out (SISO) transmission approach, where both the transmitter and the receiver use a single antenna. Other wireless communication systems use a multiple-in-multiple-out (MIMO) transmission approach, where multiple spatially separated transmit antennas and multiple spatially separated receive antennas are used to improve data rates, link quality or both. This is known as antenna diversity, spatial diversity or spatially diverse transmission.
In addition to spatial diversity, many wireless communication systems also use time diversity and frequency diversity to improve system performance. Data streams can be encoded using channel encoders of different rates and with different amounts of redundancies, and the encoded data streams can be interleaved to separate adjacent coded bits. At the receiver, the channel is estimated and equalized, and bit-streams that have been corrupted during transmission over the wireless channel are combined using error correction techniques to reconstruct the original information in the data bit-streams.